The edge of the Universe

[VanderL]

inflation, by its very nature, erases all information about prior epochs. So the distinction between the orthodox big bang and the more elaborate inflation/multiverse models is essentially a conceptual rather than an observational one.

I could be wrong about this, but doesn't this sound like admitting that the models cannot be verified?
We can't observe anything to disprove it, so it must be correct?

[anewton]

Here's one for you. Many years ago National Geograghic put out an issue comparing our space advances to the ones made at the subatomic level. The jest was: every step out learned = every step in learned. The subatomic quantum physicists have come up with this "string theory" now. Could this be the shape of our universe? I've always felt like StarQuestor on this matter. By definition alone, the univerise has no edge. Come up with a different name if you insist it is finite. Even a vaccuum is "something". Every time the scientists think they've found the smallest thing possible, just wait a week. And what if this so called "edge" is really a door to another dimension? Maybe traveling past the speed of light takes you there, too. What shape would you give our universe then?[QUOTE]All the answers are out there, we just have to find the right questions. A B Gaston

[VanderL]

I think what is happening in "advanced" science, is that people take the equations too seriously and start thinking: if the equations are ok, then it must be real. I guess Einstein started all this in a way, by doing thought experiments and proving them with math. In principle there is nothing wrong using math, but the emphasis should be on [/U]using[U] math, not the other way around. We're supposed to believe in dark matter/dark energy and a 13.7 billion year old Universe because the math tells us to. Whatever happened to common sense? We need data! (not the Startrek character).
Cheers.

[Josh]

VanderL, you know, I'm sure, that verification (ie proof) for anything is impossible. The only verification that we can have is that something isn't right (ie falsification). And then ... hypothese have to be amended - completely (as you'd like) or in part. So long as they work and survive the falsification process (hopefully without fudging )

[VanderL]

True Josh, you basically can't prove a theory to be correct, only falsify. If a theory is devised in such a way that it cannot be falsified (like "inflation by it's very nature erases all information about prior epochs"), how can we ever know it is true? In this way, such a theory can't ever be wrong and is basically useless.
Analogous to the statement that the Sun is powered by fusion reactions. This can be more or less tested by measuring the amount of neutrino's. If we don't find enough of them (the right ones, as is the case) we should start looking for alternatives. Also you will reach a point where the theory needs so many, or such basic "adjustments", that the theory can be considered to have failed.
The problem is where do you stop investing in one model and start looking for alternatives. In my opinion for a lot of theories, we have already past the point of "credibility".
Cheers.

[Josh]

No, that is a falsifiable statement. If you can test for evidence of prior epochs ... which should be possible then you can see if the theory holds. Just because the nature of things is for data to be removed in favour of something else doesn't mean that the statement is wrong. Falsification holds if the whole theory can be tested ... not one little part of it. It has to be tested in relation to the rest of the theory.

[VanderL]

You mean that inflation is falsifiable? I thought we couldn't look (measure) anything past the particle horizon, so how would we show that inflation didn't happen?

[Littlemews]

You mean that inflation is falsifiable?

many ( I guess its not may of them ><) scientist distinguish two facets of inflation, one as a theory of initial conditions for the hot big bang and the other as a model for the origin of structure in the Universe, but lately, they found out both of the theory are indeed falsifiable.

[Josh]

...by testing other things in the theory that rely on or are pertenant to this part of the theory.

[Matthew]

True Josh, you basically can&#39;t prove a theory to be correct, only falsify. If a theory is devised in such a way that it cannot be falsified (like "inflation by it&#39;s very nature erases all information about prior epochs"), how can we ever know it is true? In this way, such a theory can&#39;t ever be wrong and is basically useless.

If a statement cannot be falsified then there is a chance that the statement could be correct. Of course there is a chance that it is wrong. And it may only be un-falsifiable now, not in the future.

[Josh]

The point is, Matthew, that if it isn&#39;t falsifiable then it isn&#39;t science. Plain and simple.

[VanderL]

This problem of a supposition being untestable is a big problem in science today. We assume the sun is powered by nuclear fusion, we assume that redshift can be explained as the result of an expanding Universe, we assume that gravity is the only important force in the Universe, we assume that singularities/black holes really exist and we assume that there is dark matter needed to explain the observed motion of galaxies. We have to make sure that whenever a model is discussed the underlying assumptions are also clearly stated. We tend to forget what the assumptions are, and by repeating a story enough times we accept it as truth. Assume nothing.
Cheers.

[scott712]

Living on The Edge
The Absence of More Space to Travel Into.

I think, more than not merely finding an end to the occurance of more stars, we might someday arrive at what appears to be a solid wall in Space. Closer examination, however, will reveal that this apparent wall is nothing more and nothing less than the end of Space itself. It will seem to be a solid barrier, made of a material, but in reality it will simply be the absence of any place further to go.

[Bridh Hancock]

&#39;Edge&#39;, for me, implies a boundary; a boundary distal to a centre. On the edge of our Universe are the galaxies; all the galaxies. Very near the centre of our Universe, we have the boundary of perceivability, behind which all is a red blur; the RedBlur of the BigBang. To look back in space & time is exciting. That is our Universe&#33;? Wow&#33;&#33; To look forward, beyond this galaxy, is to look into or beyond the Edge. Bouncing back from the Edge we have detected nothing, not even with a dent in or on it. Nutrinos (nutrinoes) have been said to be coming back from there & then, having gained momentum in the great whack-back. Perhaps that idea has been knocked-back.

The BigBang was neither big, nor was there a bang. With the erruption into our time & space, surely some the super-particles moved into the centre and became the first BlackHole. As the rest of the Universe, as it spread and cooled, aggregated, exploded, irradiated, and imploded, is what we see and wonder at today. I join you in this.

Please do not obscure this document with stipple. May any artiness be outside the text box. Thank you.

Bridh Hancock

[Faulkner]

Nothing is getting answered here at all&#33;

However much I respect Sir Paul Davies & thoroughly enjoy/am enlightened by his countless books & articles, I must confess I considered his statement to be very rhetorical, just repeating what we&#39;ve all read before. (I wish he had&#39;ve delved deeper for us&#33;&#33;&#33

The fact of the matter is, we are told CONTINUALLY that a "Big Bang" event occurred in our distant past, which was a "vacuum fluctuation" FROM nothing, INTO nothing, and that this "explosion" (or perhaps "eruption" is a better word) is EXPANDING more and more into nothing.

Doesn&#39;t make sense.

For one thing, it goes against Newton&#39;s law that "for every action there is an equal and opposite reaction". That is, as the universe pushes outwards, there MUST be something pushing back&#33;

Mr Davies&#39; likening of the universe to the surface of the Earth (which we&#39;ve all heard before) goes against the latest astronomical findings that the universe is FLAT (not "open" (saddle-shaped) nor "closed" (spherical)). In other words, parallel lines don&#39;t converge/diverge, and the angles of a triangle add up to 180 degrees.

Doesn&#39;t this recent discovery tear apart the old old picture of a universe that somehow "spherically" twists back upon itself, like a "Mobius strip"?

Doesn&#39;t it mean that perhaps the universe is in fact expanding outwards from a point-like singularity? And that, if we were to by-pass the "cosmic speed limit" by utilizing a hypothetically-feasible Alcubierrean "warp drive", we could reach an EDGE???

Also, how does the latest "findings" that the universe is a decahedronal "hall-of-mirrors" illusion in our skies relate to this???

I&#39;m confused. Seems like a lot of others here are too. I think we need a much more detailed explanation from the experts&#33;&#33;&#33; (Even the NASA "cosmology" pages, tho&#39; up-to-date with latest Hubble findings, doesn&#39;t confront these fundamental issues. We are told that the universe is FLAT, but also that it is SPHERICAL, also...etc etc...). Contradictions, contradictions&#33;

[Josh]

Faulkner ... you write out your questions and I&#39;ll try and get Professor Davies to answer something a little deeper for you.

As to my humble understanding of things ... The very notion of a human trying to visualise these things is, frankly, impossible. The universe is expanding into nothing. Can you visualise nothing? No? you can visualise empty space (perhaps space is a bad word here) but not nothing. Out brains can&#39;t fathom such things. Does that mean it&#39;s not the way things are? No.

The notion that the Big Bang came from nothing isn&#39;t accurate either. The theory as far as i&#39;m aware of it is that the big bang is a direct result of a big collapse... that the universe is just one big causality loop. Therefore the universe didn&#39;t come from nothing.

As for Newton&#39;s law ... if what I said at the beginningn of this - that the universe is indeed expanding into nothing except itself - then no law is being violated.

And as to the reaching the edge in the ultra fast space ship .. still no, because there is no edge.... like the Asteroids video game analogy i made in another thread .. if you get to the "edge" you only get to the other side of the universe.

I have no idea about the rest .. but ask tell me specifically what you want me to ask Professor Davies and I&#39;m sure he&#39;ll make it clear.

[Littlemews]

I have a question :
What does a curved space-time continuum do?

[GOURDHEAD]

A curved space-time continuum constrains how things move in the universe. Newton assumed Euclidean space where parallel lines are always equidistant and objects in motion travelled in a straight line unless a force was applied to change their direction of travel. If the intrinsic nature of space-time is either spherical or saddle shaped, parallel lines are not everwhere equidistant and objects, free from force application, do not travel in straight lines. If space and time are each quantized, there is no continuum and objects travel, at or below the Planck distances, by disappearing in one "cell" and appearing in the adjacent "cell"...but I wouldn&#39;t bet much on it. :unsure:

[anewton]

But what about when things are equidistance, and parallel; but instead of traveling ing staight lines they corkscrew around and then might even join in a circle. Something like if you put a "Slinky" ( the pliable spring-shaped toy) around your arm and raised your hand to your shoulder? Isn&#39;t that like a curved space-time continuum?

[Sp1ke]

I wouldn&#39;t have thought a circular space-time continuum was impossible. That would mean if you travelled far enought in a straight line, you could end up back where you started.

Another interesting area is if space-time is simple at the macro level but curved and distorted at the quantum level. I don&#39;t fully understand it but one theory I&#39;ve heard is that in addition to the three space dimensions we are familiar with, there are around nine? other dimensions all curled up at a quantum/planck scale. That means all sorts of weird things can go on at that level but they&#39;re all smoothed out at the level we perceive things.

The one thing that seems to characterise the limits of perception is that "common sense" breaks down. Like at the quantum level, particles can exist in more than one place at once, cause and effect don&#39;t operate like normal; time might be a series of discrete points rather than a continuous flow.

[Faulkner]

Josh, I&#39;d like to write out some questions for Prof Davies, but I don&#39;t know where to start&#33;? I&#39;ve got millions of questions that really twist me up inside&#33;&#33;&#33;

The universe is expanding into nothing.

This is a statement of faith, not fact. Just in the same way that calling yourself an "atheist" is just as much based on blind faith as calling yourself "christian". In place of "nothing" we should really be saying "unknown".

Imagine yourself in a spaceship, but you are OUTSIDE the universe, literally in "nothing". What do you see outside your portholes? Blind spots? It&#39;s not a silly idea, because by analogy the universe we inhabit IS our "spaceship"&#33;

the big bang is a direct result of a big collapse

This "cyclical" idea of an expanding/contracting universe (I believe) has been disproven by the fact that the Universe is flat (not closed). The official statement from NASA is that the universe is continuing to expand (in fact, accelerating).

But if the Universe is indeed "flat", does that mean geometrically flat? Well then, the old old analogy that likens the Universe to the surface of a sphere doesn&#39;t work anymore&#33; This implies a global, 360-degree curvature...so that although finite, there is no "edge" to the Universe.

So what is the truth?

Or is it a case of "we just don&#39;t know"??? (In which case, I&#39;d like to hear experts admit it&#33;&#33;&#33

[Weaselbunny]

Originally posted by AusJosh@Nov 16 2003, 04:16 AM
Of course, you could always accelerate to Warp 10 and theoretically occupy every point in space at the same time (i would naturally assume this would include the edge)....

But then again, youd need to exist inside a science fiction series first....now theres the hard part.



-Josh

Also, if Voyager is to be believed, it would turn you into a freakish fishboy&#33;

[StarQuestor]

Excellent response there by Josh with Paul Davies explanation. Its the first time I&#39;ve read anything like it that, for me at least, adequately explains some of the counterintiveness pervasive in cosmology. It really does seem that even our most astute analogies can break down at the edge of the universe and that we simply reach a point of the truly indescribable.

[astromark]

This thread and the next are one in the same: No edge, No center. Infanite time and space. Faith in the fact as yet unproven. The thought that this might be finite does not registar. Its not logical. I do not exept nothing as an explanation of anything. We might have large areas of empty space. Its as near to nothing that I will exept. Am I alone?. . No.

[wstevenbrown]

If there&#39;s a bright center to the Universe, this is the planet that it&#39;s farthest from.-- Luke Skywalker

[John L]

Issac Asimov addressed this in the Foundation series, creating a settlement of scientists at the out edge of the galaxy so that there were only a handful of bright stars in the night sky and the dim glow of the galaxy if you lived outside the city. They settled here to avoid the chaos of the colapsing galactic empire in the hopes of founding the seed of the next empire.

Douglas Adams adressed something similar, too, with his planet Krikit, where the single star with its single planet were in the center of a dark cloud in space. To the inhabitants of this world the entire universe was their world and sun. When they finally flew out of the cloud in their first space ship and saw the galaxy, they declared war on it as it didn&#39;t fit into their universal view.

[Mr Universe]

Of course you can reach the end of the universe&#33; You just need to run fast enough :blink:

[Joff]

As a practical framework for the sci-fi novel, I would suggest that you use a solar system sitting directly "above" a spiral galaxy (ie. on the axis of rotation of that galaxy), about half the radius of the visible disk away from the centre with no other members of that galaxy&#39;s "local group" on the opposite side. This would give a view of a massive bright spiral in one direction and almost perfect darkness in the other.

The solar system would probably have to have been "ejected" from the parent galaxy (by some gravitational slingshot effect); maybe even built up outside the galaxy of the chance encounter of an ejected sun and an ejected planet. To lend a little credence to this possibility, there is a recently discovered star in the Milky Way with a velocity which will eventually take it out of the galaxy.